Identificación de las variedades en mezclas de vinos comerciales mediante espectroscopia y marcadores microsatélite
- Autores: Carme Domingo Gustems
- Directores de la Tesis: Anna Puig (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Elena Albanell Trullás (presid.), Xoán Elorduy Vidal (secret.), Raúl Ferrer Gallego (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia de los Alimentos por la Universidad Autónoma de Barcelona
- Materias:
- Enlaces
- Tesis en acceso abierto en: TESEO
- Resumen
Authenticity and traceability of wines are of interest to grapevine growing and winemaking sectors, as well as to the commercial area, regulatory agencies and consumers. The Cabernet Sauvignon, Pinot Noir, Merlot, Tempranillo, Grenache Noir and Syrah varieties are widely used, and the commercial wines resulting from the blending of these varieties have been the subject of this study. Wines are considered monovarietal when they are made exclusively from a single grapevine cultivar or with at least 85% of it. Advanced analysis methods, such as spectroscopic and molecular ones, in combination with multivariate statistical techniques have provided analytical and genetic imprints necessary to identify the grapevine varieties present in wines. Chemometrics has allowed extraction, identification and analysis of complex data matrices obtained with sensitivity and selectivity to determine the percentages of grapevine varieties. Information of every one of the one hundred and twenty-three samples analysed has not been used entirely. Instead, the visible spectra (81 variables) have been reduced with the help of the parameters of the colour space by the International Commission on Illumination. In the Fourier-transform infrared spectroscopy (1060 variables), the principal components analysis has been applied. As for the set of microsatellites (20 markers) the most discriminating have been selected by means of an analysis of the genetic variation and hierarchical clustering. As far as the spectroscopic analyses are concerned, 69.7% of the samples have been correctly classified using lightness, the red coordinate, and the chroma and tone magnitudes; 71.3% of the samples have been correctly classified with the first three principal components which accounted for 99.1% of the total variance in the infrared spectrum; and with the mid-level data fusion of the visible spectrum (lightness, the blue coordinate and chroma) and the same three principal components of the infrared spectrum, 73.0% of the monovarietal wine classes have been distinguished. Results obtained with the method based on the use of microsatellite markers have not been successful enough due to the variability in both the quantity and quality of the genetic material extracted. The principal components analysis of the matrix of the pre-treated allele frequencies has allowed us to project the results of a suitable set of four discriminatory markers in both a two-dimensional and three-dimensional space for binary and ternary blends of Cabernet Sauvignon, Pinot Noir and Merlot, respectively. With just one microsatellite marker, but with a highly significant correlation, a clear link was noticed between the height of the peaks (alleles) and the relative proportion in the case of binary blends of Pinot Noir and Cabernet Sauvignon. The combined use of spectroscopic and molecular methods has shown a great potential for the authentication of red grape varieties in commercial wine blends
